1. Field
The following description relates to image processing, and more particularly, to a technology of acquiring and processing light field data using a modulator to spatially modulate a four-dimensional (4D) light field of an image in a frequency domain.
2. Description of the Related Art
Most commercialized imaging systems show captured pictures in a single image. Recently, studies on plenoptic cameras that refocus images have been conducted. A plenoptic camera, which is also called a light field camera, obtains four-dimensional (4D) light field information of images using a microlens array (generally, a lenticular lens). The plenoptic camera provides users with various functions, such as the option to refocus an image which allows a focus plane of an image to be adjusted after the image has been taken. The plenoptic camera also allows a user the ability to view variations of an image at different view angles.
In order to acquire such light field data, angular data regarding light orientation has to be acquired as well as spatial data regarding the number of sensor pixels. As a result, resolution deterioration often occurs when obtaining the angular data. Accordingly, conventional light field imaging has failed to create high-resolution images. Because the resulting 4D data is two-dimensional (2D) spatial data plus 2D angular data received from a 2D sensor, the resolution of spatial data is lowered by the amount of angular data. For example, if 12×12 (that is, 144) pieces of angular data are needed to meet a degree of angular resolution of a lens, the resulting resolution will be reduced to 1/144 of a maximum resolution that is attained through the use of all the sensor pixels.
In addition, conventional light field systems apply uniform sampling to spatial data. The light field systems utilize either a microlens array or a light modulator. The microlens array has to be subjected to uniform sampling due to its structure in which microlenses having the same size are arranged. Likewise, in the case of a light modulator, uniform sampling is used under an assumption that spatial and angular bandwidths are uniformly assigned.
That is, existing modulators for spatially modulating light fields have been designed under an assumption that spatial data has the same bandwidth for each band of orientation data in a frequency domain. Accordingly, frequency responses created by such existing modulators appear at uniform intervals with respect to spatial data.
However, when the image information of light field data is transformed to the frequency domain, a phenomenon occurs wherein the higher the frequency domain, the less spatial data.